IE55034B1 - Synergistic avermectin combination - Google Patents

Abstract

A novel combination of one or more avermectin compounds of formula <CHEM> where the broken line indicates either a single or a double bond at the 22,23-position; n is 0 or 1, and when n is 0 a hydrogen is present at the 13-position; R1 is hydrogen or <CHEM> R2 is hydrogen or hydroxy provided that R2 is present only when the broken line indicates a single bond; R3 is sec-butyl or isopropyl; and R4 is hydrogen or methyl, with agricultural spray oil is synergistic in such a manner as to allow for a drastic reduction in the amount of active ingredient that is fully effective and also to provide a dramatic extension of the period over which such a combination is fully effective. The synergistic combination is useful as an agricultural insecticide and miticide against a variery of insects and mites which infest a variety of plants.

Description

This invention relates to a synergistic avermectin combination.

The avermectins (formerly identified as 0076 compounds) are a family of macrocvclic lactones that are highly effective against a broad range of pests which infest and are an annoyance to plants and animals. The avermeetins are active against ectoparasites and endoparasites of domestic animals, including pets and animals grown for food, also man. In addition, the compounds are very effective against arthropod· pests, which affect plants while in storage or while growing, either in the aerial portion of the plant or from the soil in which they grow. 3 55034 The avermectin compounds are isolated from the fermentation broth of a microorganism, Streptomyces averroitilis. The isolation and purification of such compounds is described in U.S.

Patent Specification No. 4,310,519. Several derivatives of the avermectin compounds have been prepared, specifically the 22,23-dihydro derivatives and the monosaccharide derivatives.

The present invention is based on the discovery that a combination of certain avermectin compounds, including certain derivatives, e.g. some of those mentioned above, with an agricultural spray oil is significantly more effective at a lower dose of avermectin and over a longer period of time than either component alone Compounds that are related to the avermectins, but which have significant chemical differences, are the milbemycins, which have also been found to be active miticides and insecticides. In tests, the ovicidal activity of such compounds has been enhanced by the addition of machine, oil. However, such activity has been demonstrated to be s'ignificity different from synergistic activity against the motile (active) stages of agricultural insect and mite pests.

The avermectin compounds that form part of the synergistic combination of the present invention have the following structural formula: OR, wherein the broken line indicates either a single or a double bond at the 22,23-positionj R^ is hydrogen or Rj is hydrogen or hydroxy provided that R2 is present only when the broken line indicates a single bond; R-j is sec-butyl or isopropyl; and R4 is hydrogen or methyl.

In accordance with the present invention, a formulation containing a synergistic combination useful against motile stages of arthropods infecting plants comprises one or more avermectin compounds having the above formula, together with 0.03 to 0.5% v/v, based on the total formulation, of an agricultural spray oil that is a highly refined hydrocarbon oil containing at least 92% unsulfonated residues or is a vegetable seed oil or mixture thereof.

The avermectin compounds isolated from the Streptomyces avermitilis fermentation broth are obtained as described in the above-mentioned U.S.

Patent Specification No. 4,310,519. Such carpounds are those of the above formula in which R^ is the sugar residue (which is ct-L-oleand'rose); the broken line indicates a single or double bond; R2 is hydroxy but is present only when the broken line indicates a single bond; R^ is sec.-butyl or isopropyl; and R4 is hydrogen or methyl . The compounds are named using a combination of letters and numbers which coordinate with the structural variations of the substituents. The following table defines the avermectin natural product compounds; Avermectin R1/A22,23 s3 24 Ala Double bond sec-butyl -CH Alb Double bond isopropyl -CH. A2a -OH sec-butyl -CH A2b -OH isopropyl -CH. Bla Double bond sec-butyl -H Bib Double bond isopropyl -H B2a -OH sec-butyl -H B2b -OH isopropyl -H 55034 Derivatives of the above 8 avermectin compounds can be prepared to form other compounds which are effective in the combination of the invention. In the Ala, Alb, Bla and Bib compounds (the H1-series" of compounds) the 22,23-double bond can be selectively reduced to a single bond to form the compounds wherein Rj is hydrogen. The catalyst selective in reducing the 22,23-double bond while not affecting the other 4 double bonds is Wilkinson's homogeneous catalyst,which is exemplified by triphenyl phosphine rhodium chloride. The procedures for making such 22,23-dihydro avermectin compounds are fully described in U.S. Patent Specification No. 4,199,569.

In addition, the outer α-L-oleandrose group can be selectively hydrolyzed to prepare the avermectin monosaccharide compounds; i.e., the compounds wherein Rj is hydrogen. Hydrolysis is most readily and most selectively effected by treating the avermectin compounds with sulfuric acid in isopropanol. The procedures for preparing such monosaccharide compounds are fully described in U.S. Patent Specification No. 4,206,205.

The agricultural spray oils that' form the second component of the combination are highly refined hydrocarbon oils, specially processed to remove sulfonated residues which may be toxic to plants, In accordance with the invention, oil with at least 92% unsulfonated residues is used. The oils are narrow distillation fractions and ate characterized by a narrow range of physical properties. In particular, they are characterized by their viscosity, measured in seconds. One of the oils useful in the combination is a narrow fraction yielding a viscosity test of 60 seconds. This commonly is called "60 second oil" and is also known by the tradenames of Sunspray 6H, Orchex, FMC NR 415, and similar 60 · second oils from Superior and Volk. This particular oil is also characterized in having a boiling point of 213°C (4151^). Another oil used in the present combination is a similar oil however, having a viscosity test of 70 seconds. This is called "70 second oil" and is also known by the tradenames of 7 75 5 0 3 4' Sunspray 7N, FMC NR 440, and similar 70 second oils from Superior and Volk. This oil is also characterized in having a boilinq point of 227°C (440 °F}.

Other typical characterizations of the present agricultural spray oils are described in the literature. See, for example, Canadian Patent 964,482.

The agricultural spray oils may also be a vegetable seed oil or a mixture of vegetable seed oils, which, as thev are known in the agricultural industry, are crop seed oils produced from the particular crop from which their name is derived. Included in the vegetable oils suitable for the compositions of the present invention are cotton seed oil, rapeseed, peanut oil, sunflower oil, linseed oil, safflower oil, soybean oil, corn oil, olive oil and blends of the above oils such as cotton seed oil plus soybean oil; cotton seed oil plus peanut oil; cotton seed oil plus olive oil; corn oil plus linseed oil; corn oil plus soybean oil; as well as blends of any two or more of the above disclosed vegetable oils. In addition, the present agricultural spray oil may be a mixture of a vegetable oil or oils and the above described hydrocarbon oils.

These oils have been used alone to combat mite infestations in plants; however, the concentrations used were generally of the order of 1 to 2%. In addition, such oil formulations at the 1 to 2* concentration were used in combination with insecticides. It is known that when it is used under these conditions, the oil physically smothers the eggs, thus preventing their maturing into the motile θ staaes of development. That is, the oil ants as an ovicide.

In the present invention the oil is used in combination with the avermectin compound in concentrations similar to that used in the prior art. Furthermore, much less of the avermectin compound need be used. The combination of the agricultural spray oil and the avermectin provides effective protection against the motile stages of the mites and insects while the use of higher concentrations of the oil provides ovicidal effects. In the . formulation of the invention, the agricultural spray oil is used in concentrations of from 0.03 to 0.5% on a volume-to-volume basis of the final formulation. Preferably the concentration of the agricultural spray oil is from 0.06 to 0.5%, particularly about 0.25%. The lower concentrations are preferred when, because of the nature of a particular plant, or because of the sensitivity of a particular stage of growth of a plant, a spray containing higher concentrations cannot be used because of phytotoxicitv.

The avermectin compounds are preferably used in the synergistic combination at concentrations of from 0.03 to 8 parts per million (ppm), particularly 0.25 to 3 ppm, and especially from 1 to 3 ppm. These dilute solutions can provide optimum field control of the mite populations.

The combination of the avermectin with the agricultural spray oil provides the unexpected benefits of being able to use less of each of the 9 9 55034 ingredients as well as providing a lonqer duration of action.

It is also advantageous to use less of each of the ingredients since the avermectins are very expensive and the agricultural spray oils, under certain circumstances can be phytotoxic, or at least contraindicated. The surprising observation that the present combination has a considerably prolonged duration of action is a great benefit in that costly reapplications and reinfestations are avoided.

The avermectin and the agricultural spray oil combination is prepared using a solvent solution or emulsion of the avermectin compound or compounds, the agricultural spray oil, a surfactant and sufficent water to dilute the mixture to the desired concentration.

Thp surfactants which may be used to emulsify the oil and the avermectin in the aqueous formulations are any of the non-phytotoxic surfactants, which are customarily used in preparing formulations for use on agricultural crops.

The surfactants or surface active agents particularly suited for use in the compositions of the present invention are ionic or nonionic surface active compounds generally well known to the art. Surface active agents are suitable as a class for use according to the present invention. The nature of surface active agents is well known and such auents generally have an oleophilic portion of the molecule, usually of hydrocarbon nature, and another polar portion of the molecule, which may be provided by various functional groups such as hydroxyl, sulfate, carboxyl, carbonyl, amino, nitro, amide, ether, ΙΟ sulfonate, phosphate or phosphite. Examples of suitable classes of surface active agents are alkali metal salts of fatty acids, alkali metal salts of sulfated fatty acids, fatty acid glycerides, sulfonated or sulfated fatty acid esters or amides, alkali metal sulfates, alkali metal alkyl sulfonates, alkali metal aryl sulfonates, alkali metal alkyl lauryl sulfonates, quaternary ammonium halides, alkali metal salts of alkylated naphthalene, sulfonic acid, polyethylene sorbitol esters of fatty acids, fatty acid amides of alkanol amines, condensation products of ethylene oxide and polyalkylene glycols, sorbitan esters, alkyl substituted phosphoric acids and alkali metal salts of alkyl phenol sulfonates. Examples of individual surface active agents are given for example in Kirk et al., ENCYCLOPEDIA OP CHEMICAL TECHNOLOGY, Volume 13, pages 515-517 (1954).

The ingredients are combined using formulation techniques well known to those skilled in the art.

The synergistic combination of the invention may be used against agricultural arthropod pests to provide effective protection from the motile stages of such mites and insects while the plant is growing or while · the crops from such plants are in storage. In particular, this combination is effective against mites of the order acarina such as the two spotted spider mite (Tetranychus urticae), the citrus red mite (Panonychus citri), the citrus rust mite (Phyllocoptruta oleivora), and the like. Insects of the order homoptera, coleoptera and lepidoptera are likewise susceptible to this combination , in 11 particular the black bean aphid (Aphis fabae), Colorado potato beetle (Leptinotarsa decemlineata), Mexican bean beetle (Epilachna varivestis) ; and cabbage looper (Trichoplusia ni).

In using the compounds of this invention, the individual avermectin components may be prepared and used in that form. Alternatively, mixtures of two or more of the individual avermectin components may be used, as well as mixtures of the parent avermectin compounds, other avermectin compounds, or other active compounds not related to the avermectins and the compounds of this invention.

In the isolation of the avermectin compounds, which serve as starting materials for the present processes, from the fermentation broth, the various avermectin compounds will be found to have been prepared in unequal amounts. In particular an "a" series compound will be prepared in a higher proportion than the corresponding "b" series compound. The weight ratio of "a" series to the corresponding "b" series is about 75:25 to 99:1. The differences between the "a" series and "b" series is constant throughout the avermectin compounds and consists of a sec-butyl group and an iso-propyl group respectively at the 25-position. This difference, of course, does not interfere with any of the present reactions. In particular, it may not be necessary to separate the "b" components from the related "a" component. Separation of these closely related compounds is generally not practised since the "b" compound is present only in a very small percent by weight, and the structural difference has negligible effect on the reaction processes and biological activities.

In particular, for the preferred B1 and A1 compounds, it has been found that the starting materials for the compounds of this invention are very often prepared in a ratio of about 80% avermectin Bla and Ala and 20% avermectin Bib or Alb. Thus the preferred composition of this invention is one which contains at least 80% of the "a" component and not more than 20% of the "b" component.

EXAMPLE 1 Effects of Avermectin Bla/Blb and Agricultural Spray Oil on Citrus Rust Mite on Oranges.

In a test of the effectiveness of avermectin compounds and agricultural spray oil {Sunspray 6N) used alone and in combination against the citrus rust mite on Marrs oranges, the following results were observed after spraying the orange trees to runoff with the listed concentration of the ingredients.

The data are given in Table I in terms of the mean numbers of rust mites observed per sq cm on the indicated number of days following the spraying. The agricultural spray oil was reapplied on day 53. The last column "% Russet" indicates the percent of fruit that were downgraded due to the effects of the mites. 135503 4 \ 4) 4J I 0 4) V U U Qt V + Φ <<· in O CM OO o J3 u -Q ΟΛΗ 0) H UH --- e co ea u \ u\ V « 4) fi >H >H < CO < W HO 9 ϋ >, H IQ b b O' & < CQ 53034 1 4 EXAMPLE 2 Effects of Averraectin Bla/Blb and Agriculture Spray Oil on Citrus Rust Mite on 5 Grapefruit_ The The procedure followed in Example 1 is repeated on grapefruit trees except that both the 0.04 oz/100 gal treatment of avermectin and the agricultural spray oil were reapplied on day 53. results are given in Table II. 15 10 ον r- p- γ ιο ιηιη «η m ro μ m ο m ο m eg oj o r* o u EH in co co v co Φ *r cg m vo rt iw in σι w v o o H O' M rH v o V Ό co rt P* e o c c •Η Ή 4J *> OX) OX) V r-4 Ο) W e a e a u\ u \ 41 A 4» A O W Μ H on m e eg in 1-4 Γ*· o © co in in CO PH O ON m H o\ + tfP v m O CN oe o 9H JJ -H HQ I 9H ii-H I Η O I 9 _> l ϋ >i 0 >i » W IQ ·Η IQ I U U MU i mn. nA. in o H H 55034 16 3 5 0 3 4 In analyzing the result of Examples 1 and 2 it is noted that the 2 concentrations of the avermectin applied without oil achieved only moderate control of the mites although the lower dosage in the 5 grapefruit had to be reapplied because of increasing mite population levels. The agricultural spray oil, also applied twice, achieved a level of control better than the control group, but not very effective considering the high percent of russet downgrading of 10 the fruit. The combination of a low dose of the avermectin and the agricultural spray oil applied once achieved in the orange test a mite count 60 times better than the low dose and 15 times better than higher dose at the end of the test. Percent 15 russet was only 5% for the combination and 16 and 35% for the high and low doses respectively, 31% for the oil alone and 51% for the control. For the grapefruit, compared with the avermectin results, the combination had 135 and 155 times less mites. The 20 percent russet was likewise improved at 8% for the combination 22 and 23% for avermectin alone, 40% for the oil alone and 70% for the control.

EXAMPLE 3 25 Effects of Avermectin and Agricultural Spray Oil Against Motile Stages of the Two-Spotted Spider Mite on Bean Plants in the Laboratory._ In this test various concentrations of avermectin Bla/Blb alone and in combination with two different levels of agricultural spray oil were tested. In addition, the agricultural spray oil alone was tested at 2 different concentrations. 17 17 5 S Ο 3 4 Table III shows the results where avermectin Bla/Blb was sprayed onto the plants containing a mixed mite population of adults and nymphs. Mortality counts were taken 5 and 11 days post-spray. Table IV 5 represents a similar test however the infestation was applied 7 days after the plant was sprayed to measure residual control. Table V is a compilation of the data of Tables III and IV and gives the estimated effective dosage for avermectin Bla/Blb alone and 10 with the agricultural spray oil. 185503 Γ> Q Ο Ο Q WO HO ο ο ο οο ΟΟΟΟΜ GDOMHU o i" ο ο ο ο σι CM Ο Ο Ο Ο ΜΟΟ ΟΝ Η V Γ"* 10 ΙΛ ^ Ο σι σι Is» cm ^ Η CM (Μ F** σι ιη Ρ» η υζ t** ο ιο in cmπιηηΗη η* ο ιη η οι σι ο σι ρ* ρ* Η ΟΟΟ σι Η on rtH ΜΗΜβΝ C0 is σι βΗ in in uuu z zz «ιηΐην Η Γ- Ο ** CM Η Η Η CM ρ» ν η η © Η C*· CM Η CM Η Η Η Η Η ο o is ο ο ο 09000 Η Η ΗΗ ο ιη ο ο σι Ο σιο Ο IS Η Η Η ΟΟΟ Ο Η Ο Ο Ο σι η η Η η «μ ΝΗ Ο Ο Ο Ο Ο ΟΟΟΟΗ Η Η Η Ο ΗΟ 0«Ρ σι r-σι ιη σι Η Η Η ID CM 10 ΟΟΟ ο ο ο ο σι ο ο ο ο οι Ο CM Ο ΟΝΝΙβΟnnt ΟΟΟΟΗ ΗΟΟΟΜ cm σι ιη \ο σι® η η ois ο η® μ win ® σι ιή ο η γ- γ* ιο cm Η Η Η Η ιη η ιο σι ιο cm Ν σι (η η Η CM Η Η CM ο cm ο in η η in ίΑΝφΟΗ (ΜΗ Ο Ο Ο ιη η in cm «ο ιη η η ο ηο ©οο ιη η ιη (Μ ιο in cm η ο η ο ο ο ο ΟΟΟ R U Ζ C ϋ J2 Β u < a \ <ο Η α C Η U η * σΐΗ ΛΛ <*Μ U Δ Ο UH# ββ«η >, br\(N fQ φ Η · Dt < β ο σι * σι η <Η Δ Ο Η <0 Λ Η >ι <0 Ο U Η Η Ο Ο 3 W Ο >ι 1)Ή Q C b u ο εη α Ο < w ο γμ m CM 19 55034 ο •«•4 4Jt i I tu o 0 g | § 8 d B c «•p4 JJ illsis in 100 100 100 20 100 o o o o o Η H o o o o O O O o O o O 0 0 5 o o Ο» 0 fr L 100 100 100 5 100 100 60 9 0 0)00 in m o o o o o o VO cn O 0 10 41 in *** ΗΝΌΝ Η Η H O' H 21 15 4 „8B· rn co %%% 100 100 100 7 100 100 78 15 PfflOO in o o o o o o m \o O o o © 04 co r-cn co rH ο \o m σ% •t οnin O' CO o* i—4 P#l CO CO ««T O Ul U") O 0\ Φ CO V ΝΝΗΦ r*«2 Η 04 p* in CO m rH CO r- w e ΟΟβΜΛΗ ΟΟΙΛΝ Nr^OO inroHin N v6 W #-4 0 0 0 m γο ι-i in (N so fn #-4 Si II « 44 *9 » O • SO V <0 S3 Bs° pr .Si? 1^5 ·§& U M 4) flS U h O* Ui Milieu) < Λ * W 0 * $8r 8i in o i-4 04 in oi 2 20 55034 TABLE V Estimated effective dosages of Avermectin Bla/Blb combinations. 90 CONTACT TEST RESIDUAL TEST 5 5 Days Post-Sorav 11 Days Post-Sorav 4 Days Post-Infestation 13 Days Post-Infestation ADULTS Avermectin Bla/Blb .1 .25 .25 .4 10 Avermectin Bla/Blb .0063 with .125% Agricultural Spray Oil .025 .03 .05 15 Avermectin Bla/Blb .0063 with .031% Agricultural Spray Oil .02 .03 NYMPHS .125 Avermectin Bla/Blb .015 .1 .4 .2 Avermectin Bla/Blb .0063 with .125% Agricultural Spray Oil .0125 .031 .125 20 Avermectin Bla/Blb .01 with .031% Agricultural Spray Oil ,04 .125 LARVAE .125 Avermectin Bla/Blb —. .1 - .4 25 Avermectin Bla/Blb — with 125% Agricultural Spray Oil .0063 — .02 30 Avermectin Bla/Blb — with .031% Agricultural Spray Oil .0063 — .125 21 21 55034 In the above tests it is noted that the combination treatment is more effective than either treatment alone such that lower concentrations of the avermectin are effective for longer periods of time. In addition, since in the avermectin and combination treated plants many mites are recovered, although most are dead, it is apparent that the effect is not as an ovicide which would be expected with treatment with an oil. The presence of motile mites demonstrates that the eggs were not killed. However, the high mortality observed against the adults, nymphs and larvae populations also demonstrates that the treatment is highly effective aqainst the motile stages of the mite.

EXAMPLE 4 Effects of Avermectins and Agricultural Spray Oil on the Two-spotted Spider Mite on Bean Plants_ Bean plants were treated with various concentrations of avermectin Bla/Blb, Sunspray 6N agricultural spray oil, and combinations thereof, and 7 days thereafter were challenged with a mixed population of the two-spotted spider mite. Table VI gives the results of observations made 6 and 12 days after the challenge. A significant improvement in activitv is noted when the combination is applied to the plant. 22 55034 TABLE 71 EVALUATION OP AVERMECTIN Bla/Blb WITH AGRICULTURAL SPRAY OIL TWO-SPOTTED SPIDER HITE Avermectin Bla/Blb PPM Sunspray 6N Oil % -6-Day Reading Adults Larvae Adults -12-Day Reading----- Nymphs Larvae 1.0 _ 99 0 100 41 05 10 0.25 - 0 0 36 1 3 0.063 - 0 0 0 0 0 1.0 1.0 100 66 100 100 0.25 1.0 100 21 100 - 100 0.063 1.0 100 0 100 67 95 15 1.0 0.25 100 57 100 _ 100 0.25 0.25 100 0 100 100 100 0.063 0.25 100 0 100 81 95 1.0 0.063 100 57 100 100 100 0.25 0.063 100 0 100 - 100 20 0.063 0.063 88 0 100 45 — - 7 0 0 0 0 — 1.0 0 0 0 0 0 — 0.25 15 0 0 0 0 — 0.063 0 0 - - - Bean plants were challenged with mixed mite population seven days after treatment. 55034 23 EXAMPLE 5 Effects of Avermectin Bla/Blb, and Agricultural Spray Oil on the Citrus Red Mite on Lemon Trees_ 5 Lemon trees with an ongoing population of citrus red mites were sprayed once with 8 ppm of avermectin Bla/Blb, agricultural spray oil and a combination thereof. The agricultural spray oil was applied at a rate of 3 pints per 100 gallons of spray 10 (.375%). The data is summarized in Table VII. 2455034 CO r·*· r- • • e , CO CM vo VO ip co CN o CO Γ CO o • • tn in rP ΙΟ CO + H rP in σ» c •H to >t 0) (3 i> J-l Π3 a Γ- O CO r- Φ M • e »4 o <5· CO rP p P CO CM H CO CM Φ + • CO 4J 0] IP 4J p < C co r- o O' O H ♦H P Q + H P ♦H 0 W 3 jn r- co CO 0 in VO ro ' in rp c 1 (N rO ro H 0 c H (0 - nj ip Ct< Δ U 1 ip p 0$ H > a a a Effects of Avermectins and Agricultural Spray Oils on Bean Aphids_ Bean plants infested with the Bean aphids were treated with avermectin Bla/Blb, agricultural spray oil and mixtures thereof and the results analyzed 1 and 5 days after treatment. The results are summarized in Tables VIII and IX, and demonstrate that the oil has very little effect alone, and together the treatment is greatly and synergistically improved. 26 55034 TABLE VIII THE EFFECT OF AGRICULTURAL SPRAY OIL ON THE INSECTICIDAL EFFICACY OF AVERMECTIN Bla/Blb Bean Aphid on Bean Plants 5 % Emulsifiable Concentration (PPM) % Mortality^/ Oil of avermectin Bla/Blb Day 1 Day 5 .25 .5 0 90 .25 5 80 .125 0 85 10 .063 0 80 0 0 5 .063 .5 25 50 .25 30 50 .125 10 60 15 .063 15 55 0 5 0 0 1.0 30 35 0.5 20 25 0.25 25 0 20 0.125 10 0 0 0 0 All values are means of 2 replicates 1/ 2755034 TABLE IX Influence of an agricultural spray oil on the efficacy of aphid averraectin Bla/Blb used against the bean Percent avermectin Bla/Blb Percent Oil (ppm) Control9 0.25 0.5 87 0.125 53 0.031 17 0.0078 0 0 0 0.125 0.5 80 0.125 33 0.031 0 0.0078 0 0 0 0.063 0.5 73 0.125 30 0.031 0 0.0078 0 0 0 0 0.5 47 0.125 3 0.031 0 0.0078 0 0 0 a Mean of three replicates EXAMPLE 7 Preparation of an Aqueous Plant Spray Containing Avermectin Bla/Blb and an Agricultural Spray oil _-__ For evaluation of synergistic activity in the laboratory, a 90% oil emulsion was formulated by adding 1 gram of Agrimul 26-B emulsifier to 9 grams of Sunspray 6N 60 see spray oil. This oil emulsion was treated as a pure (100%) oil and added to solutions of avermectin Bla/Blb to prepare known concentrations of the avermectins and oil as shown in the foregoing examples.

For dilute sprav applications under field conditions, 0.04 oz (1.134 g) of avermectin Bla/Blb formulated as 0.03 lb per gallon (3.6g/L)soluble liquid was poured into 100 gal (379 L) of water. To this resulting solution was added with agitation 1 quart of agricultural spray oil to provide an emulsion containing 0.04 oz (1.134 g) avermectin Bla/Blb (3 ppm) and 0.25% oil in 100 gal (379 L) of water.

Claims (11)

55034 3·9 CH,

1. A formulation containing a synergistic combination useful against motile stages of arthropods infecting plants that comprises one or more avermectin compounds having the formula: where the broken line indicates either a single or a double bond at the 22,23-position; ^ is hydrogen or R2 is hydrogen or hydroxy, provided that R2 is present only when the broken line indicates a single bond; R3 is sec-butyl or isopropyl; and r4 is hydrogen or methyl, 30 5 5 0 3 4 and 0.03 to 0.5% v/v, based on the total formulation, of an agricultural spray oil that is a highly refined hydrocarbon oil containing at least 92% unsulfonated residues or is a vegetable seed oil or 5 mixture thereof.

2. A formulation as claimed in Claim 1 in which the amount of avermectin compound or compounds is 0.03 to 8 ppm, based on the total formulation.

3. A formulation as claimed in Claim 2 in which the 10 amount of avermectin compound or compounds is 0.25 to 3 ppm and the amount of agricultural spray oil is 0.06 to 0.5% v/v, both based on the total formulation.

4. A formulation as claimed in Claim 3 in which the amount of avermectin compound or compounds is 1 to 3 15 ppm and the amount of agricultural spray oil is about 0.25% v/v, both based on the total formulation.

5. A formulation for use against the motile stages of mites and insect pests of plants comprising an inert carrier, a compound having the formula set forth in 20 Claim 1, and 0.03 to 0.5% v/v, based on the total formulation, of an agricultural spray oil that is a highly refined hydrocarbon oil containing at least 92% unsulfonated residues or is a vegetable seed oil or mixture thereof. 25

6. A formulation as claimed in Claim 5 in which the amount of avermectin compound or compounds and the amount of agricultural spray oil are as defined in claim 2, 3 or 4. 31 31 55034

7. A formulation as claimed in Claim 5 or 6 that also includes an anionic and/or a non-ionic surfactant.

8. A method of killing or inhibiting the motile 5 stages of arthropod pests of plants, comprising applying to them a formulation as claimed in Claim 1.

9. A method of killing or inhibiting the motile stages of arthropod pests of plants, comprising 10 applying to them a formulation as claimed in any one of Claims 2 to 7.

10. A formulation according to Claim 1, substantially as hereinbefore described and exemplified.

11. A method according to Claim 8 or 9 of killing or 15 inhibiting the motile stages of arthropod pests of plants, substantially as hereinbefore described and exemplified. F. R. KELLY & CO., AGENTS FOR THE APPLICANTS.